Monthly Archives: April 2015

A crime scene on Alcatraz

Seabird nesting season is in full force on Alcatraz. This wonderful time of the year is a rare chance to see many of the Bay Area’s seabirds nesting and raising their young. In numbers (and in volume) are the Western gulls. Last year they counted in at around 2000 pairs.


However, their arrival always comes with a bit of apprehension. The gulls of course need material to make nests and must also claim territory. Both of these tasks mean that plants are torn up and shredded, and all too often these are garden plants!


We have come to expect a bit of damage but with the native grass, Carex praegracilis, lawn that was planted with plugs we were a bit nervous if the plugs would take root and be strong enough to withstanding the tugging by gulls.


The plugs were planted at the beginning of November when the rains would hopefully start. While we had some showers we had to supplement with hand watering too from our rainwater catchment. About 1/3 of the lawn was planted and now 5 months along, the plugs have started to send out stolons and are spreading.


On a recent sunny morning, while checking the gardens over, I noticed a puzzling crime scene – the grasses were being shorn off close to their bases.


Carex plugs being nibbled to their bases. Photo by Shelagh Fritz

Carex plugs being nibbled to their bases. Photo by Shelagh Fritz

Guilty by past behavior, I immediately suspected the gulls. But, the telltale sign of shredded vegetation was not present. In fact, the missing tops of the grasses were actually gone! What could this be? We don’t have deer or rabbits and yet the grass looked ‘nibbled’.


Examining the scene closer, I spied the ‘evidence’ left behind – droppings. Sure enough Canada geese had found our lawn. There are maybe 3 pairs of geese on the island and they were making our lawn their morning buffet.


Canada goose 'evidence'. Photo by Shelagh Fritz

Canada goose ‘evidence’. Photo by Shelagh Fritz

For all of our planning and thinking of possible ‘what could go wrong scenarios’, we had overlooked the population of geese and their liking of grass.


Luckily, few plugs have been pulled out, the geese are proving to be more grazers, and hopefully the plugs will continue to grow. Mowing actually helps grasses get thicker and encourages them to send out more stolons.


The lawn is slowly being ‘mown’ from left to right, but at least the plugs are being fertilized too.

The native sedge lawn being 'mown' by Canada geese. Photo by Shelagh Fritz

The native sedge lawn being ‘mown’ by Canada geese. Photo by Shelagh Fritz


With the mandated 25% cut in water usage in California, I’m so relieved we choose to have a native sedge replicate the look of a lawn. Our ‘lawn’ will be low maintenance and will only require 2” of water per month to stay relatively green throughout the summer months.


As Alcatraz is a destination, I’m hoping that visitors will take notice of our drought tolerant lawn and ask questions. The lawn will also be a topic on our garden tours and offered as an alternative.

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